Predation efficiency of Anopheles gambiae larvae by aquatic predators in western Kenya highlands

Abstract Background The current status of insecticide resistance in mosquitoes and the effects of insecticides on non-target insect species have raised the need for alternative control methods for malaria vectors. Predation has been suggested as one of the important regulation mechanisms for malaria vectors in long-lasting aquatic habitats, but the predation efficiency of the potential predators is largely unknown in the highlands of western Kenya. In the current study, we examined the predation efficiency of five predators on Anopheles gambiae s.s larvae in 24 hour and semi- field evaluations. Methods Predators were collected from natural habitats and starved for 12 hours prior to starting experiments. Preliminary experiments were conducted to ascertain the larval stage most predated by each predator species. When each larval instar was subjected to predation, third instar larvae were predated at the highest rate. Third instar larvae of An. gambiae were introduced into artificial habitats with and without refugia at various larval densities. The numbers of surviving larvae were counted after 24 hours in 24. In semi-field experiments, the larvae were counted daily until they were all either consumed or had developed to the pupal stage. Polymerase chain reaction was used to confirm the presence of An. gambiae DNA in predator guts. Results Experiments found that habitat type (P < 0.0001) and predator species (P < 0.0001) had a significant impact on the predation rate in the 24 hour evaluations. In semi-field experiments, predator species (P < 0.0001) and habitat type (P < 0.0001) were significant factors in both the daily survival and the overall developmental time of larvae. Pupation rates took significantly longer in habitats with refugia. An. gambiae DNA was found in at least three out of ten midguts for all predator species. Gambusia affins was the most efficient, being three times more efficient than tadpoles. Conclusion These experiments provide insight into the efficiency of specific natural predators against mosquito larvae. These naturally occurring predators may be useful in biocontrol strategies for aquatic stage An. gambiae mosquitoes. Further investigations should be done in complex natural habitats for these predators

The role of cow urine in the oviposition site preference of culicine and Anopheles mosquitoes

<p>Abstract</p> <p>Background</p> <p>Chemical and behavioural ecology of mosquitoes plays an important role in the development of chemical cue based vector control. To date, studies available have focused on evaluating mosquito attractants and repellents of synthetic and human origins. This study, however, was aimed at seasonal evaluation of the efficiency of cow urine in producing oviposition cues to <it>Anopheles gambiae </it>s.l. and <it>Culex quinquefasciatus </it>in both laboratory and field conditions.</p> <p>Methods</p> <p>Oviposition response evaluation in laboratory conditions was carried out in mosquito rearing cages. The oviposition substrates were located in parallel or in diagonal positions inside the cage. Urine evaluation against gravid females of <it>An. arabiensis </it>and <it>Cx. quinquefasciatus </it>was carried out at Day 1, Day 3 and Day 7. Five millilitres (mls) of cow urine was added to oviposition substrate while de-chlorinated water was used as a control. In field experiments, 500 mls of cow urine was added in artificial habitats with 2500 mls of de-chlorinated water and 2 kgs of soil. The experiment was monitored for thirty consecutive days, eggs were collected daily from the habitats at 7.00 hrs. Data analysis was performed using parametric and non-parametric tests for treatments and controls while attraction of the oviposition substrate in each species was presented using Oviposition Activity Index (OAI).</p> <p>Results</p> <p>The OAI was positive with ageing of cattle urine in culicine species in both laboratory and field experiments. The OAI for anopheline species was positive with fresh urine. The OAI during the rainy season was positive for all species tested while in the dry season the OAI for culicine spp and <it>Anopheles gambiae </it>s.l., changed with time from positive to negative values.</p> <p>Based on linear model analysis, seasons and treatments had a significant effect on the number of eggs laid in habitats, even though the number of days had no effect.</p> <p>Conclusion</p> <p>Oviposition substrates treated with cow urine in both laboratory and field conditions have shown that cow urine left to age from 1-7 days has an influence on oviposition behavioural response in mosquitoes. The analysis of microbial colonies for decaying urine should be investigated along with its associated by-products.</p

Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

<p>Abstract</p> <p>Background</p> <p>The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae) regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>on different life history traits of both species under different densities and constant food supply in the habitats of the same size under semi-natural conditions.</p> <p>Methods</p> <p>Experiments were set up with three combinations; <it>Cx. quinquefasciatus </it>alone (single species treatment), <it>An. gambiae </it>s.s. alone (single species treatment); and <it>An. gambiae </it>s.s. with <it>Cx. quiquefasciatus </it>(co-habitation treatment) in different densities in semi field situation.</p> <p>Results</p> <p>The effect of co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>was found to principally affect three parameters. The wing-lengths (a proxy measure of body size) of <it>An. gambiae </it>s.s. in co-habitation treatments were significantly shorter in both females and males than in <it>An. gambiae </it>s.s single species treatments. In <it>Cx. quinquefasciatus</it>, no significant differences in wing-length were observed between the single species and co-habitation treatments. Daily survival rates were not significantly different between co-habitation and single species treatments for both <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus</it>. Developmental time was found to be significantly different with single species treatments developing better than co-habitation treatments. Sex ratio was found to be significantly different from the proportion of 0.5 among single and co-habitation treatments species at different densities. Single species treatments had more males than females emerging while in co-habitation treatments more females emerged than males. In this study, there was no significant competitive survival advantage in co-habitation.</p> <p>Conclusion</p> <p>These results suggest that co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>in semi-natural conditions affect mostly <it>An. gambiae </it>s.s. body size. Hence, more has to be understood on the effects of co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>in a natural ecology and its possible consequences in malaria and filariasis epidemiology.</p

Genome sequence of the tsetse fly (Glossina morsitans):Vector of African trypanosomiasis

Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein-encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology.IS

Surgical treatment options and its adverse outcomes among patients with urolithiasis at KCMC, 2014 to 2018

Purpose: The study aimed to evaluate surgical treatment options and its adverse outcomes among patients with urolithiasis at Kilimanjaro Christian Medical Centre (KCMC). All patients who were diagnosed with urolithiasis and underwent surgical intervention from January 2014 to December 2018 were enrolled.Method and material: This was a hospital based descriptive cross-sectional study conducted at the institute of urology, KCMC, Moshi, Tanzania. Urology theatre registry was used to obtain patients’ registration numbers then the files were retrieved from medical records. Relevant information was extracted using structured data collection tool. STATA version 14.1 was used for analysis and a P value of 0.05 was regarded to be statistically significant.Results: Among seventy-eight subjects, sixty-two were males and sixteen were females with male to female ratio of 3.8:1. Patients aged 4 years to 90 years. Majority 57 (73.1%) underwent open surgery treatment and only 17 (21.8%) had adverse outcome after treatment. In multivariate analysis patients treated with endoscopy had more than six times higher odds of adverse outcomes compared to counterpart though this was not statistically significant (OR: 6.65; 95% CI: 0.82, 53.87)Conclusion: Open surgeries have been observed to have better outcome compared to endoscopy surgeries among urolithiasis patients as most of the adverse outcomes were more observed among patients treated with endoscop

Contemporary Challenges in Street Trader-Customer Interaction Through Mobile Devices in Dodoma, Tanzania

Part 1: Communities, ICT-Enabled Networks, and DevelopmentInternational audienceStreet trading is a common form of informal work carried out by almost one million Tanzanians. Majority of street traders use mobile devices to interact with customers. Despite this interaction, there is no abundant information showing if their interaction is mainly effective and does not face challenges. This study investigated the challenges faced by street traders and customers interacting through mobile devices in Dodoma, Tanzania. Qualitative data were collected using in-depth interviews with 42 street traders and 32 customers, followed by focus group discussion with eight street traders and six customers. Thematic analysis was used to analyze the data. The results show that street traders and customers occasionally interact using mobile phones. However, that interaction is challenged by issues connected to financial, technical and social aspects. These challenges are; lack of reliability among mobile phone interacting customers, mobile network problems, lack of business communication transparency, deep-rooted customary practices and perceptions of street trading, poor customer care, lack of consensus over mobile business etiquette, poor quality of product pictures, short mobile internet bundle validity, mobile phone battery life, and costs of mobile handset, transactions, vouchers, packages, and transport. The results call for the option of bundle and transaction cost reduction, network infrastructure improvement and provision of education to street traders and customers so that they realize the significance of business interaction using mobile devices contrary to what is happening recently, as well as abiding by communication ethics to minimize the likely challenges

The role of a best practice alert in the electronic medical record in reducing repetitive lab tests

Harini Bejjanki,1 Lazarus K Mramba,2 Stacy G Beal,3 Nila Radhakrishnan,1 Rohit Bishnoi,1 Chintan Shah,1 Nikhil Agrawal,4 Neil Harris,3 Robert Leverence,1 Kenneth Rand3 1Division of Hospital Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA; 2Statistics, Department of Internal Medicine, University of Florida, Gainesville, FL, USA; 3Department of Pathology, Immunology, &amp; Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA; 4Department of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA Background: The recommendations of the American Board of Internal Medicine Foundation&rsquo;s &ldquo;Choosing Wisely&reg;&rdquo; initiative recognize the importance of improving the appropriateness of testing behavior and reducing the number of duplicate laboratory tests.Objective: To assess the effectiveness of an electronic medical record Best Practice Alert (BPA or &ldquo;pop up&rdquo;) intervention aimed at reducing duplicate laboratory tests and hospital costs.Design: Comparison of the number of duplicated laboratory tests performed on inpatients before and after the intervention.Setting: University of Florida Health Shands Hospital, Gainesville, FL, USA, during 2014&ndash;2017.Intervention: The electronic medical record intervention was a BPA pop-up alert that informed the ordering physician if a recent identical order already existed along with the &ldquo;ordering time&rdquo;, &ldquo;collecting time&rdquo;, &ldquo;resulting time&rdquo;, and the result itself.Main outcome measures: Percentage change in the number of inpatient duplicate orders of selected clinical biochemistry tests and cost savings from reduction of the duplicates. Student&rsquo;s t-test and beta-binomial models were used to analyze the data.Results: Results from the beta-binomial model indicated that the intervention reduced the overall duplicates by 18% (OR=0.82, standard error=0.016, P-value&lt;0.000). Percent reductions in 9 of the 17 tests were statistically significant: serum hemoglobin A1C level, vitamin B12, serum erythrocyte sedimentation rate, serum folate, serum iron, lipid panel, respiratory viral panel, serum thyroid stimulating hormone level, and Vitamin D. Additionally, important cost savings were realized from the reduction of duplicates for each lab test (with the exception of CRP) with an estimated overall savings of $72,543 over 17 months in the post-intervention period.Conclusions: The present study included all hospital inpatients and covered 17 clinical laboratory tests. This rather simple and low-cost intervention resulted in significant reductions in percentage duplicates of several tests and resulted in cost savings. The study also highlights the role of hospitalists in quality improvement. Keywords: laboratory, testing, health care, cost

In vitro and in vivo studies on anti-malarial activity of Commiphora africana and Dichrostachys cinerea used by the Maasai in Arusha region, Tanzania

Abstract Background Traditional medicinal plants are one of the potential sources of anti-malarial drugs and there is an increasing interest in the use and development of traditional herbal remedies for the treatment of malaria and other ailments. This study was carried out with the aim to investigate the phytochemical screening, cytotoxic effect and antiplasmodial activities of Dichrostachys cinerea and Commiphora africana. Both plants are used by the Maasai in Tanzania in suspected malaria and other diseases. No previous work appears to have investigated the potential anti-malarial activity of the two plants. Methods This study aimed to investigate the in vitro anti-malarial activity of methanol and dichloromethane extracts of the two plants against chloroquine sensitive (D6) and chloroquine resistant (Dd2) strains of Plasmodium falciparum. The anti-malarial property was assessed by the lactate dehydrogenase method (pLDH). The in vivo anti-malarial study was carried out using the Peters’ 4-day suppressive test in Plasmodium berghei in Balb/c mice. Cytotoxic tests were carried out using monkey kidney epithelial cell line in [3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay. Qualitative phytochemical screening was carried out using standard methods of analysis. Results The phytochemical screening of plant extracts revealed the presence of alkaloids, flavonoids, tannins, steroids, triterpenoids, glycosides and saponins. However, alkaloids were absent in most plant extracts. The dichloromethane extracts of C. africana (stem bark); D. cinerea (stem bark) and methanol extracts of D. cinerea (whole stem) all showed promising in vitro anti-malarial activities. All other extracts did not show any significant anti-malarial activity. The two most promising extracts based on in vitro studies, DCM extracts of C. africana (stem bark) and D. cinerea (stems bark), equally exhibited very significant anti-malarial activities in the mouse model. They exhibited parasite suppression rates of 64.24 and 53.12%, respectively, and considerable improvement in weight and survival rate. Most plant extracts were not cytotoxic except for DCM extract of D. cinerea (whole stem) CC50 (29.44 µg/mL). Conclusion The findings of this study provide scientific evidence supporting the traditional use of the plants in the treatment of malaria by the Maasai in Arusha region, Tanzania. Consequently, further work including bioassay-guided fractionation and advanced toxicity testing may yield new anti-malarial drug candidates from the two plants

Research in Progress: Holistic Climate Service Prototypes for Farmers in Tambuu, Tanzania

Part 3: Southern-Driven Human-Computer InteractionInternational audienceUrgent efforts are needed to address climate change and changing climate variability. Solutions are needed at economic, political, scientific, educational, as well as technological domains. Our previous research in Tambuu, Tanzania, shows that the acute information needs of the community are credible and trustworthy weather information, knowledge in best uses of weather information, and education about best farming practices. Delivering the information for end users in Tambuu is a challenge in itself. Based on these results and following the principles of System Action Design Research, we developed prototypes for future climate services together with local farmers in Tambuu community. These prototypes and our future plans are presented in this research-in-progress paper